Ballpoint pen for water-soluble ink



y 1959 YUKIO' HORIE 'BALLPOINT PEN FOR WATER-SOLUBLE INK Filed Sept. 18,1967 FIG. I

l 3 IO 3 9 FIG. 3

FIG. 4

CAP I I CARTRIDGE HOLDING BARREL (MAIN BARREL) United States Patent3,446,564 BALLPOINT PEN FOR WATER-SOLUBLE INK Yukio Horie,Musashino-shi, Tokyo-to, Japan, assignor to Dainihon Bungu KabushikiKaisha, Tokyo-to, Japan, a joint-stock company of Japan Filed Sept. 18,1967, Ser. No. 668,443 Claims priority, application Japan, Mar. 31,1967, 42/ 19,881 Int. Cl. B43k 7/02 U.S. Cl. 401-209 2 Claims ABSTRACTOF THE DISCLOSURE This invention relates generally to ballpoint pens andmore particularly to a new and improved ballpoint pen having highlydesirable features for writing with watersoluble inks.

Heretofore, various kinds of ballpoint pens for writing withwater-soluble inks have been proposed, but up to the present time, asfar as I am aware, these pens have invariably been accompanied by one ormore difliculties such as dripping of ink resulting in blotches, poorfeeding of ink to the ball, and rapid depletion of ink.

It is an object of the present invention to provide a new ballpoint penof high utility and performance in which these difliculties have beenovercome.

More specifically, an object of the invention is to provide a ballpointpen for water-soluble ink of simple construction which has a large inkstoring capacity, uninterrupted and smooth, yet regulated, feeding ofink to the ball, and means whereby air venting with respect to thestored ink is accomplished, yet the ink is prevented from leaking outeven under adverse conditions.

According to the present invention, briefly summarized, there isprovided a ballpoint pen for water-soluble ink which has an outer holderbarrel directly serving as an ink reservoir, a ball holder tightlyfitted in and through the front end of the barrel and holding a ball atits front end and a wick in its interior, and an air venting andpressure relieving device consisting essentially of an inner cylinder, astopper, an ink flow resisting device, an ink absorber, and a cap plugwith a vent hole, which device has the functions of covering the rearend of the barrel, air venting the varrel interior, that is, permittingair to enter the barrel to maintain pressure equilibrium as the ink inthe barrel is consumed, relieving increased pressure within the barreldue to abnormal impact or temperature rise by permitting some ink tooverflow into the inner cylinder, and preventing this overflow ink fromleaking out through the venting path.

The nature, principle, utility, and details of the invention will bemore clearly apparent from the following detailed clescripion withrespect to preferred embodiments of the invention when read inconjunction with the accompanying drawing, in which like parts aredesignated by like reference numerals.

In the drawing:

FIG. 1 is a side elevational view, in longitudinal section, showing theessential organization of a ballpoint pen embodying the invention;

3,446,564 Patented May 27, 1969 FIG. 2 is a cross sectional view takenalong the plane indicated by line II-II in FIG. 1;

FIG. 3 is a fragmentary side elevational view, in longitudinal section,showing another embodiment of the invention; and

FIG. 4 isa longitudinal section of the ballpoint pen of this inventionwherein the holder barrel is indicated as a cartridge type.

Longitudinal directions herein referred to by the terms front and rearrespectively designate directions toward and away from the pen writingpoint.

Referring to the drawing, the ballpoint pen shown therein has a holderbarrel l constituting an outer casing and provided near its rear endwith an ink stopper 3 fitted into the hollow interior. of the barrel 1and having a central hole 2. The stopper 3 coaxially supports, withinthe barrel 1, an inner cylinder 5 tightly fitted at its rear end intoand through the hole 2 and having a closed front end 4 which has a sharpfront tip. The front end 4 has near its front tip a small diameter,air-vent hole 6. A hollow ballpoint holder 7, rotatably holding at itsfront end a ball 7a, istightly fitted at its rear end into and throughthe front end of the barrel 1 and contains a wick 8 inserted into theinterior through the rear end thereof for the purpose of feeding ink aregulated manner to the ball 7a.

Near the rear end of the inner cylinder 5, there is inserted agas-permeable plug 10 made of a sponge-like material, a fibre bundle, orthe like, preferably a water repellent material made of a siliconeresin. A gas-permeable absorber material 9 is disposed to the rear ofthe stopper 3 and is prevented fromcontacting the ,gaspermeable plug 10.A cap plug 12 is fitted into the rear end of the barrel 1 and has acentral air-vent hole 11.

The ballpoint pen of the above described organization according to theinvention operates in the following manner.

First, the barrel 1 is filled with water-soluble ink through the frontend of the barrel (with the ball holder 7 removed), and then the ballholder 7 is tightly fitted into the barrel front end. The ink thenoccupying the space between the barrel 1 and the inner cylinder 5 istransferred and regulated by the wick 8 to reach the ball 7a, whereuponthe pen is ready for writing.

As the ink is consumed, the outside air enters through the rear air venthole 11 and, passing through the gaspermeable absorber material 9 andthe gas-permeable plug 10, enters through the narrow hole 6 into theinterior of the barrel 1 thereby to facilitate the smooth feeding of theink.

Since the narrow hOle 6 is very small, the ink within the barrel 1 doesnot readily flow into the inner cylinder 5, and leakage of the veryslight amount of ink which normally enters the inner cylinder 5 isresisted by the gas-permeable plug 10 and, furthermore, is absorbed bythe absorber material 9, whereby the ink is prevented from leaking outfrom the rear end of the barrel 1 through the rear vent hole 11.

In another embodiment of the invention as illustrated in FIG. 3, a thintube 13 is used in'place of the gaspermeable plug 10 of the precedingexample illustrated in FIG. 1. The thin tube 13 is fitted at its rearend into and through a stopper 3a having a projecting plug part which isfitted into the rear end of the inner cylinder 5. In all other featuresof organization, this ballpoint pen is identical to the pen describedhereinabove and illustrated in FIG. 1.

By the organization of the ballpoint pen according to the presentinvention as described above, several advantageous features are affordedas follows. Since the ink is charged directly into the interior of thebarrel, the quantity of the ink which can be stored is large, wherebythe total opisometric Writing distance between charges is long.Furthermore, the ink is fed continuously to the ballpoint by its ownhydrostatic head and thereby is fed steadily and smoothly, wherebyinterrupted writing due to breaks in the ink film on the ball isprevented.

Another feature of the instant pen is that, when the ink in the barrelis subjected to a severe physical impact or expands because of atemperature rise, the resulting excessive pressure is relieved by theescape of some ink through the small hole 6 into the inner cylinder 5,whereby accidental leakage of the ink to the outside is prevented.Furthermore, the gas-permeable plug 10 functions to brake abrupt flow ofthe ink within the inner cylinder 5 and, further, provides resistance tothe migration of the ink toward the gas-permeable absorber material 9.

A further feature of the ballpoint pen of the invention resides in thesharp front tip 4 of the inner cylinder 5 whereby, when ink is beingcharged into the barrel by means of a hypodermic syringe and needle, thetip of the needle is deflected laterally by the front tip 4, and closingof the needle outlet opening by the inner cylinder surface is therebyprevented. Accordingly, charging of the ink is facilitated.

In actual use, the main holder barrel of the ballpoint pen is shaped asshown in FIG. 4. That is, the front part of the main barrel is as sameas the shape of ordinary writing pens for the sake of convenience inholding the same at the time of writing, and the rear part of it isreduced in diameter. To this rear part of reduced diameter of the mainbarrel, a holding barrel having the same diameter as the front partthereof is fitted by means of a screw thread or any other appropriatemanner. The writing point of the pen i protected by a cap. Thus, whenthe ink in the main barrel is used up completely, this main barrel isdiscarded by being removed from the holding barrel and replaced with anew barrel. In other words, the main barrel is designed to be of areplaceable cartridge type to save trouble in filling ink in the barrel.

It should be understood, of course, that the foregoing disclosurerelates to only preferred embodiments of the invention and that it isintended to cover all changes and 4 modifications of the examples of theinvention herein chosen for the purposes of the disclosure, which do notconstitute departures from the spirit and scope of the invention as setforth in the appended claims.

I claim:

1. A ballpoint pen for water-soluble ink comprising: an outer, hollow,holder barrel serving as a case and a reservoir for ink; a stopperhaving a central hole, said stopper being tightly fitted in the interiorof the barrel near the rear end thereof; an inner cylinder having a rearend tightly fitted into and through said central hole and having aclosed front end with a small air-vent hole therein; resistance means inthe form of a thin tube fitted at the rear end thereof into and throughsaid stopper, said resistance means permitting passage of airtherethrough but resisting passage of ink; a gas-permeable ink absorberfitted in the interior of the barrel rearwardly of the stopper; a capplug having a central air-vent hole fitted into the rear end of thebarrel; and a ball holder tightly fitted in and through the front end ofthe barrel forwardly of said closed from end of the inner cylinder andholding a ball at the front tip thereof and a wick for controllablyfeeding ink from the barrel interior to the ball.

2. A ballpoint pen as claimed in claim 1 in which said gas-permeable inkabsorber is a porous waterrepellent structure made of a silicone resin.

References Cited UNITED STATES PATENTS 1,980,625 11/1934 Laforest l2172,654,108 10/1953 Scelsi 40l209 2,847,975 8/1958 Lawton 40l217 3,125,0713/1964 Nakada 40l217 FOREIGN PATENTS 248,282 7/1966 Austria.

507,266 12/ 1951 Belgium.

806,331 6/1951 Germany.

LAWRENCE CHARLES, Primary Examiner.

